1. Field of the Invention
The present invention relates to a wireless communication device and a wireless communication method.
2. Description of the Related Art
Conventionally, a technique for communicating through a relay station by a plurality of wireless communication devices (mobile stations), each of which performs a half-duplex wireless communication is known. A transmitting frequency on a mobile station side is the same as a receiving frequency at the relay station, and the receiving frequency on the mobile station side is the same as the transmitting frequency on a relay station side. It is difficult for the relay station to simultaneously transmit and receive at the same frequency. Therefore, the transmitting frequency and the receiving frequency at the relay station are separated by a predetermined frequency. All mobile stations transmit at the same frequency and receive at the same frequency, which enables a one-to-one or one-to-many (group communication) communication among mobile stations.
A half-duplex wireless communication device cannot receive a signal relayed from the relay station while transmitting a signal. Therefore, it is not possible to confirm whether or not a transmitted signal has been transmitted in a communication area (whether or not the wireless communication device itself exists in a communication area). For example, Japanese Laid-open Patent Publication No. 11-32005 discloses a technique, by which a mobile station transmits a signal indicating a communication-area confirmation request to a base station, the base station transmits a signal indicating a communication-area confirmation response to the mobile station only when the signal indicating the communication-area confirmation request is normally received from the mobile station, and the mobile station determines that the mobile station (wireless communication device itself) exists in a communication area only when the signal indicating the communication-area confirmation response is normally received from the base station.
However, in the technique disclosed in Japanese Laid-open Patent Publication No. 11-32005, there is a problem that the mobile station is required to transmit a special signal for confirming whether or not the wireless communication device itself exists in the communication area (a signal indicating the communication-area confirmation request) to the base station, and thus communication processing becomes complicated.